• Journal of Microbiology and Biotechnology
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• v.21 no.12
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• pp.1264-1269
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• 2011

Interleukin-2 (IL-2) is a vital cytokine secreted by activated T lymphocytes, and plays an important role in the regulation of cellular functions and immunity of animals. In this study, the recombinant duck IL-2 (rduIL-2) was secretory expressed in Pichia pastoris (P. pastoris). The recombinant P. pastoris strain was cultured in shake flasks and then scaled up in a 5.0-l bioreactor. The result showed that the maximal fresh-cell-weight of 594.1 g/l and the maximal $OD_{600}$ of 408 were achieved in the bioreactor. The rduIL-2 was purified by two steps of purification procedures, and approximately 311 mg of rduIL-2/L fermentation supernatant was obtained. SDS-PAGE showed that the purified rduIL-2 constituted a homogeneous band of ~16 kDa or ~14 kDa corresponding to the glycosylated or non-glycosylated duIL-2 protein in size, respectively. The bioactivity of rduIL-2 was determined by lymphocyte proliferation assay. The result indicated that the rduIL-2 greatly promoted the proliferation of ConA-stimulated lymphocytes in vitro. The P. pastoris expression system described here could provide promising, inexpensive, and large-scale production of the rduIL-2, which lays the foundation for development of novel immunoadjuvants to enhance both the immunity of ducks against various infectious pathogens and vaccine efficacy.

• Journal of Microbiology and Biotechnology
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• v.2 no.3
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• pp.166-173
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• 1992

The expression of Bacillus subtilis $\alpha$-amylase from the phoA-amyE fusion gene in recombinant E. coli was investigated under various environmental conditions. The overexpression of cloned $\alpha$-amylase caused retardations in cell growth and synthesis of alkaline phosphatase (AP) from the chromosomal phoA gene. The change of culture temperature from $37^\circ{C}$ to $30^\circ{C}$ increased the specific activities of both $\alpha$-amylase and $\beta$-lactamase by six and two times, respectively, whereas the AP activity remained unchanged. The experiments with chlorampenicol (a translation inhibitor) suggested the enhancement of $\alpha$-amylase activity at $30^\circ{C}$, and this was partly due to the stability of $\alpha$-amylase itself. The further decrease of the temperature to $25^\circ{C}$ slowed down both the cell growth and cloned-gene expression rate. The $\alpha$-amylase activity showed a maximum at pH of 7.4 while alkaline phosphatase was most effectively produced at pH of 8.3.

• Journal of Plant Biotechnology
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• v.48 no.3
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• pp.156-164
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• 2021

Spirodela polyrhiza, from the Lemnaceae family, are small aquatic plants that offer an alternative plant-based system for the expression of recombinant proteins. However, no turion transformation protocol has been established in this species. In this study, we exploited a pB7YWG2 vector harboring the eYFP gene that encodes enhanced yellow fluorescent protein (eYFP), which has been extensively used as a reporter and marker to visualize recombinant protein localization in plants. We adopted Agrobacterium tumefaciens-mediated turion transformation via vacuum infiltration to deliver the eYFP gene to turions, special vegetative forms produced by duckweeds to endure harsh conditions. Transgenic turions regenerated several duckweed fronds that exhibited yellow fluorescent emissions under a fluorescence microscope. Western blotting verified the expression of the eYFP protein. To the best of our knowledge, this is the first report of an efficient protocol for generating transgenic S. polyrhiza expressing eYFP via Agrobacterium tumefaciens-mediated turion transformation. The ability of turions to withstand harsh conditions increases the portability and versatility of transgenic duckweeds, favoring their use in the further development of therapeutic compounds in plants.

• 한국생물공학회:학술대회논문집
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• 2005.04a
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• pp.210-213
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• 2005

The suppression of apoptosis during the cell culture might increase recombinant protein production. In the present study, the effects of anti-apoptotic agents on the apoptosis of recombinant Chinese Hamster Ovary cells and the production of Iduronate 2-sulphatase(IDS) were investigated Cell density slightly increased when $2{\mu}M$ of EGCG and $10{\mu}g/mL$ of STR-G were added to culture medium after two days. It was observed that the percentage of apoptotic cells was decreased in the culture with STR-G, and Bcl-2 expression level was enhanced in both culture with STR-G and EGCG. These results suggest that G418 and EGCG are effective anti-apoptotic agents for increasing the productivity of IDS with recombinant CHO-DG44.

• BMB Reports
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• v.31 no.3
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• pp.287-295
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• 1998

Acetolactate synthase (ALS) is the first common enzyme in the biosynthesis of L-Ieucine, L-isoleucine, and L-valine. The sulfonylurea-resistant ALS gene from Nicotiana tabacum was cloned into the bacterial expression vector pGEX-2T. The resulting recombinant plasmid pGEX-ALS3 was used to transform Escherichia coli strain XL1-Blue, and the mutant tobacco ALS (mALS) was expressed in the bacteria as a protein fused with glutathione S-transferase (GST). The fusion product GST-mALS was purified in a single step on a glutathione-Sepharose column. ALS activities of 0.9-2.5 ${\mu}mol/min/mg$ protein were observed in the GST-mALS, and the Km values for pyruvate, FAD, and TPP were 10.8-24.1, $(1.9-8.9){\times}10^{-3}$, and 0.14-0.38 mM, respectively. The purified GST-mALS was resistant to both the sulfonylurea and the triazolopyrimidine herbicides, and lost its sensitivity to end products, L-valine and L-leucine. For comparision, the tobacco wild-type recombinant ALS fused with GST, GST-wALS, was also characterized with respect to its pyruvate and cofactor bindings. These results suggest that the purified mutant recombinant tobacco ALS was functionally active, that the mutations resulting in herbicide resistance has affected pyruvate and cofactor bindings," and that the two classes of herbicides interact at a common site on the plant ALS.

• Journal of Microbiology and Biotechnology
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• v.16 no.7
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• pp.1026-1031
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• 2006

The optimization of the production of a fusion protein containing the antigenic domain 1 (AD-1) is of a great importance, considering its use in diagnostic tests. The fusion protein is produced by the fermentation of a recombinant strain of Escherichia coli containing the plasmid Mbg58, which expresses the AD-1 (aa 484-650) of human cytomegalovirus glycoprotein B as a fusion protein together with aa 1-375 of ${\beta}-galactosidase$. An important characteristic of promoters (lac and derivatives) used in recombinant protein production in E. coli is their inducibility. Induction by IPTG is widely used for basic research; however, its use in large-scale production is undesirable because of its high cost and toxicity. In this work, studies using different inducers and carbon sources for the production of a fusion protein containing the AD-l were performed. The results showed that lactose could be used as an inducer in the fermentation process for the production of this protein, and that expression levels could exceed those achieved with IPTG. The use of lactose for protein expression in E. coli should be extremely useful for the inexpensive, large-scale production of heterologous proteins in E. coli. Addition of sucrose to the fermentation medium improved the yield of recombinant protein, whereas addition of fructose or trehalose decreased the yield.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.05a
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• pp.954-957
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• 2015

A recombinant baculovirus vector systems were composed of genes of polyhedron promoter, vesicular stomatitis virus G (VSVG), polyA, cytomegalovirus (CMV) promoter, enhanced green fluorescent protein (EGFP), and protein transduction domain (PTD). These recombinant baculovirus vector system were transfected into various cell lines and tissues and confirmed gene transfer and expression of these vector systems with only control vector system. From the result, gene transfer and gene expression of recombinant baculovirus vector systems were superior in terms of efficacy and safety than in the control vector system.

• Proceedings of the Korean Society of Embryo Transfer Conference
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• 2002.11a
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• pp.100-100
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• 2002

As an preliminary experiment for making transgenic animals producing human follicle stimulating hormone (hFSH), we tried to express recombinant hFSH gene in vitro. hFSH is a heterodimeric glycoprotein hormone produced in the anterior pituitary gland. The hormone is essential in the regulation of reproductive processes, such as follicular development and ovulation. Genes encoding the common gonadotrophin alpha subunit and FSH-specific beta subunit were inserted into retroviral vectors under the control of the rat beta actin promoter. Gene transfer to the Chinese hamster ovary (CHO) cells was done by infection of the retroviruses harvested from PT67 packaging cells transfected with recombinant retrovirus vector DNA. After selection with G4l8, PCR and RT-PCR analyses of the G4l8-resistant CHO cells showed successful transfer and expression of both ${\alpha}$ and ${\beta}$ fragments of the FSH gene.

• BMB Reports
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• v.37 no.5
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• pp.556-564
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• 2004

A recombinant Fab monoclonal antibody (Fab) C37, previously obtained by phage display and biopanning of a random antibody fragment library against Burkholderia pseudomallei protease, was expressed in different strains of Escherichia coli. E. coli strain HB2151 was deemed a more suitable host for Fab expression than other E. coli strains when grown in media supplemented with 0.2% glycerol. The expressed Fab fragment was purified by affinity chromatography on a Protein G-Sepharose column, and the specificity of the recombinant Fab C37 towards B. pseudomallei protease was proven by Western blotting, enzyme-linked immunosorbent assay (ELISA) and by proteolytic activity neutralization. In addition, polyclonal antibodies against B. pseudomallei protease were produced in rabbits immunized with the protease. These were isolated from high titer serum by affinity chromatography on recombinant-Protein A-Sepharose. Purified polyclonal antibody specificity towards B. pseudomallei protease was proven by Western blotting and ELISA.

• Journal of Microbiology and Biotechnology
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• v.12 no.5
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• pp.753-759
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• 2002

$\beta$-Cyclodextrin glucanotransferase ($\beta$-CGTase) was overproduced extracellularly using recombinant E. coli by transforming the plasmid pECGT harboring a secretive signal peptide. The $\beta$-CGTase gene of alkalophilic Bacillus firmus var alkalophilus was inserted into the high expression vector pET20b(+) containing a secretive pelB signal peptide, and then transformed into E. coli BL2l(DE3)pLysS. The optimum culture conditions fer the overproduction of $\beta$-CGTase were determined to be TB medium containing 0.5% (w/v) soluble starch at post-induction temperature of $25^{\circ}C$. A significant amount of $\beta$-CGTase, up to 5.83 U/ml, which was nine times higher than that in the parent strain B. firmus var. alkalophilus, was overproduced in the extracellular compartment. A pH-stat fed-batch cultivation of the recombinant E. coli was also performed to achieve the secretive overproduction of $\beta$-CGTase at a high cell density, resulting in production of up to 21.6 U/ml of $\beta$-CGTase.